Hearing by bone conduction as a phenomenon, i.e., conduction of sound to the inner ear through the bones of the skull, is known. Electromagnetic transducers combine properties such as small size, wide frequency range, high impedance, and efficient energy transformation; hence, they are widely used in hearing aid applications. Such transducers include a vibrator plate and bobbin assembly and a small air gap therebetween. By superimposing a signal magnetic flux generated by a coil wound around a bobbin (central portion) the force in the air gap, between the vibrator plate and bobbin assembly, is produced.
The size of the air gap is crucial to the energy efficiency of the vibrator and should therefore be kept as small as possible, while at the same time, collapse of the air gap needs to be avoided. For this reason, a very precise adjustment of the air gap is very important.
Therefore, there is a need to provide a solution that makes it possible to provide a very precise and simple adjustment of the air gap.